On Asymptotic Classification of Solutions to Nonlinear Regular and Singular Third- and Fourth-Order Differential Equations with Power Nonlinearity

For the equation $$\displaystyle{ y^{(n)} + p_{ 0}\,\vert y\vert ^{k}\ \mathrm{sign}\,y = 0, }$$ in the cases n = 3, 4, p0 > 0 or p0 1 and singular nonlinearity 0 < k < 1 asymptotic classification of all solutions are given.